Support spindle for windable material coils

ABSTRACT

A support spindle includes a central shaft defining a rotation axis and forming a connecting portion and a supporting portion extending from the connecting portion along the rotation axis, cam seats formed in the supporting portion, locking bodies arranged radially outside the supporting portion and in contact, by cam-follower members, with the cam seats, a supporting cage connected to the central shaft and which accommodates the locking bodies so the locking bodies can slide radially to the rotation axis with respect to the central shaft and rotate about the rotation axis with respect to the central shaft. A relative rotation between the locking bodies and the central shaft along an angular stroke causes a radial displacement of the locking bodies between a retracted position and an expanded position. The cam-follower members form a first convex cam surface in contact with a second concave cam surface of the corresponding cam seat.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Italian PatentApplication No. 102020000019849, filed Aug. 10, 2020, which is herebyincorporated by reference herein.

DESCRIPTION

The present invention relates to a support spindle for winding andunwinding coils or rolls of windable material on a winding core (orspool), in particular, but not limited to, coils or rolls of web-like orthread-like material, e.g., paper, fabric, corrugated cardboard,banknotes, polymer film, aluminum film, textile yarns and filaments,glass fibers, carbon fibers, electrical cables, etc.

In the manufacturing, processing, and handling processes of the web-likeor thread-like material wound on a coil, it is necessary to wind andunwind the web-like material under controlled material speed and tensionconditions.

It is known to wind the web-like material onto a winding core (orspool), typically a cylindrical tube made of cardboard, plastic, ormetal, and engage the winding core from two opposite sides by means oftwo support spindles. The support spindles sustain the core and theentire coil of the material wound during the material winding orunwinding process and transmit a winding rotating moment or brakingmoment as well as possible desired translatory shifts to the coil. Tothis end, the support spindles are connected to actuation motors orbraking systems which allow precise control of the winding/unwindingspeed and tension of the material on the core.

Mechanical-pneumatic support spindles are known, which can be insertedinto the winding core and configured to take a radially retractedconfiguration to (torsionally) disengage the winding core and allow theinsertion and extraction of the spindle into/from the winding core, aswell as a radially expanded configuration to (torsionally) engage thewinding core, where the retraction and expansion of the support spindlecan be carried out by means of a suitable pneumatic actuation system ofthe support spindle, irrespective of the interaction between the supportspindle and the coil of wound material.

So-called “torsional” support spindles are also known, which can beinserted into the winding core and configured to take a radiallyretracted configuration to disengage the winding core and allow theinsertion and extraction of the spindle into/from the winding core, aswell as a radially expanded configuration to engage the winding core,where the retraction and expansion of the support spindle are driven byrotational movements of the winding core inserted onto the spindle, withrespect to a central shaft of the spindle. This rotational movement ofthe winding core rotates an outer cage and outer sectors of the spindlewith respect to the central shaft, and this relative rotation betweenthe outer cage/outer sectors and the central shaft causes (e.g. byvirtue of a wedge or cam effect) a displacement of the outer sectorsradially outwards and in pressing engagement against an intrados of thewinding core.

The torsional support spindles of the prior art have the disadvantagethat the torsional engagement and disengagement with the winding core isnot immediate and precisely coincident with the application of a coilwinding moment or with the application of a core release moment althoughdependent on a real rotational movement and thus subject to undesiredslipping phenomena between the spindle and the winding core and angularengagement/disengagement positions which are not controllable withcertainty and not very precise.

Therefore, the need is felt for torsional support spindles with alimited or shorter angular actuation (engagement/disengagement) strokes,with a well controllable and more immediate engagement and disengagementeffect, and which are less subject to undesired slipping during thesteps of engaging and disengaging the winding core.

It is thus the object of the present invention provide a support spindlefor winding and unwinding coils or rolls onto a tubular core, havingfeatures such as to avoid at least some of the drawbacks mentioned withreference to the prior art.

It is a particular object of the present invention to provide a supportspindle, having features such as to limit or reduce the angularactuation (engagement/disengagement) strokes compared to the prior art.

It is a further particular object of the present invention to provide asupport spindle, having features such as to make the engagement anddisengagement with the winding core more controlled and immediate inresponse to a rotational feeding of the winding core with respect to thesupport spindle, and to reduce undesirable slipping during the steps ofengaging and disengaging the winding core.

These and other objects are achieved by a support spindle for windingand unwinding coils of windable material on a core according to claim 1.

The dependent claims relate to preferred and advantageous embodiments ofthe invention.

In order to better understand the invention and appreciate theadvantages thereof, some non-limiting exemplary embodiments thereof willbe described below with reference to the accompanying drawings, inwhich:

FIG. 1 is an exploded perspective view of a support spindle, accordingto an embodiment of the invention;

FIG. 2 is a sectional view on a radial plane of the support spindle inFIG. 1,

FIGS. 3 and 4 are cross-sectional and side views of a support spindleaccording to an embodiment, in a retracted configuration,

FIGS. 5 and 6 are cross-sectional and side views of the spindle in FIGS.3 and 4, in a radially expanded configuration,

FIG. 7 is a front view of a central shaft of a support spindle accordingto an embodiment,

FIG. 8 is a front view of a central shaft of a support spindle accordingto a further embodiment,

FIG. 9 is a perspective view of a two-diameter support spindle accordingto a further embodiment,

FIGS. 10, 11 are sectional views of a central shaft of the two-diametersupport spindle in FIG. 9,

FIGS. 12 and 13 show two opposite support spindles disengaged from (FIG.12) and engaged with the winding core of a coil of windable material, inwhich the coil is full and can be under unwinding,

FIG. 14 is a sectional view taken along the section plane XIV-XIV inFIG. 13,

FIGS. 15, 16, 17, 18 are sectional views of parts of support spindlesaccording to the embodiments, having different engagement diameters withthe winding core and being in a fully radially expanded configuration,

FIG. 19 is a side view of a support spindle according to an embodiment,having an ejection and positioning flange in a fully retracted position,

FIG. 20 shows the support spindle in FIG. 19 with the ejection flange ina fully advanced position,

FIG. 21 is a front view of the support spindle in FIG. 19,

FIG. 22 is a perspective view of the support spindle in FIG. 19.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, the term “front” orientation relates tothe orientation of sides, faces, surfaces, etc. in the insertiondirection of the support spindle on a winding core, the term “rear”orientation relates to the orientation of sides, faces, surfaces, etc.in the retraction direction of the support spindle out of the windingcore, unless otherwise specified. The terms “radial,” “circumferential,”and “axial” relate to the longitudinal axis of the support spindle,which corresponds to the rotation axis of the support spindle and thewinding core engaged by the latter, unless otherwise specified.

With reference to the figures, a support spindle 1 to engage a tubularwinding core 2 for winding and unwinding windable material 3 to form acoil 4, comprises:

A) a central shaft 5 defining a rotation axis 6 and forming:

-   -   a connecting portion 7 on a rear side 8 of the support spindle        1,    -   a supporting portion 9 extending from the connecting portion 8        along the rotation axis 6 towards a front side 10 of the support        spindle 1,    -   a plurality of cam seats 11 formed in the supporting portion 9,        B) a plurality of locking bodies 12 arranged radially outside        the supporting portion 9 and in contact, by means of        cam-follower members 13, with the cam seats 11,        C) a supporting cage 14 connected to the central shaft 5 and        forming a plurality of guide seats 15 which accommodate and        position the locking bodies 12 so that the locking bodies 12 can        slide radially to the rotation axis 6 with respect to the        central shaft 5 and rotate about the rotation axis 6 with        respect to the central shaft 5, where the cam seats 11 and the        cam-follower members 13 are shaped so that a relative rotation        between the locking bodies 12 and the central shaft 5 about the        rotation axis 6 causes a radial displacement of the locking        bodies 12 between a radially inner, retracted (end-of-stroke)        position (FIG. 3), and a radially outer, expanded        (end-of-stroke) position (FIG. 5), for disengaging and engaging        the support spindle 1 with the winding core 2.

According to an advantageous embodiment, to each of said locking bodies12 is associated exactly and only one of said cam follower members 13.

According to a further advantageous embodiment, each locking body 12forms a radially internal surface 42 facing the support portion 9 andforming a partially cylindrical cavity 43 extending in a directionparallel to the rotation axis 6, in which said cavity 43 rotatablyaccommodates one of said cam follower members 13 having an elongatedcylindrical shape and being extended in a direction parallel to the axisof rotation 6,

wherein between respectively one locking body 12 and the support portion9 there is interposed:

-   -   only one of said cam follower members 13 having elongated        cylindrical shape, or    -   a group of said cam follower members 13 of elongated cylindrical        shape, in which all said cam follower members 13 of the group        are positioned and oriented concentric with each other and        parallel to the rotation axis 6.

An angular stroke 16 of relative rotation of the locking bodies 12 withrespect to the central shaft 5 about the rotation axis 6 (angularactuation stroke), corresponding to a total radial stroke 24 of thelocking bodies 12 from the retracted (end-of-stroke) position and theexpanded (end-of-stroke) position and vice versa, is preferably lessthan or equal to 30° or preferably less than or equal to 15°, and

possibly, the cam seats (11) and the cam-follower members (13) limit therelative rotation of the locking bodies (12) with respect to the centralshaft (5) about the rotation axis (6) to a maximum relative rotationangle either less than or equal to 60° or less than or equal to 30°,i.e. twice the angular actuation stroke 16, and

possibly, the cam-follower members 13 form a first convex cam surface 17in contact with a second concave cam surface 18 of the corresponding camseat 11, and

possibly, on a sectional plane orthogonal to the rotation axis 6, thefirst convex cam surface 17 has a circular arc shape and the secondconcave cam surface 18 has a symmetrical shape with respect to asymmetry plane 19 radial to the rotation axis 6, with an arc-shapedbottom section 20 and two opposite side sections 21, which may besubstantially straight, mutually defining a cam angle 22 in the rangefrom 100° to 145° or from 100° to 120°, preferably from 105° to 115°,even more preferably of 110°.

With further advantage, a radial depth 23 of the cam seat 11 is greaterthan the total radial stroke 24 of the locking bodies 12 between theretracted (end-of-stroke) position and the expanded (end-of-stroke)position, and a circumferential width 25 of the cam seat 11 is greaterthan four times the radial depth 23 of the cam seat 10.

By virtue of the particular geometry of the cam seat 11, a significantradial displacement of the locking bodies 12 is achieved with a limitedor shorter angular actuation (engagement/disengagement) stroke ascompared to the prior art and with a more controlled and immediateengagement and disengagement effect. As a result, during the steps ofengaging and disengaging the support spindle 1 with the winding core 2,the slipping of the winding core 2 with respect to the support spindle 1and the uncertainties of the actual angular position of the coil 4 withrespect to a planned angular position thereof are reduced. Furthermore,the geometry of the cam seat 11 and the cam-follower member 13 allow amutual rolling and/or sliding with less friction, and thus an activationof the locking bodies with comparably small pulling forces on thewindable material. Furthermore, the geometry of the cam seat 11 and thecam-follower member 13 achieve a reduction in wear compared to the priorart, resulting in an increase in the service life of the support spindle1.

Detailed Description of the Central Shaft 5.

In accordance with an embodiment (FIG. 1), the central shaft 5 can bemade of a metal material, such as steel, for example. The connectingportion 7 may comprise a connecting flange in the shape of a circulardisc or circular ring, extending in a plane orthogonal to the rotationaxis 6, and forming a plurality of fixing holes 26 for connecting thesupport spindle 1 to a supporting and moving system 27 with an actuationmotor 28 and/or with a brake 29 for performing controlled positioningand rotation of the support spindle 1 in order to engage/disengage thewinding core 2 and to unwind and/or wind the coil 4 (FIGS. 12, 13, 14).

The supporting portion 9 has an elongated shape with a preferablycylindrical outer surface in which the cam seats 11 are formed. The camseats 11 can extend parallel to the rotation axis 6 along the entiresupporting portion 9 and have a constant cross-section shape along therotation axis 6.

The supporting portion 9 preferably comprises three cam seats 11 evenlydistributed at an angular pitch of 120°.

The bottom section 20 may advantageously be shaped as an arc of a circlehaving a radius in the range from 17 mm to 23 mm, preferably from 19 mmto 21 mm, even more preferably of 20 mm.

The radial depth of the cam seat 11, measured along the symmetry plane19 up to an outer circumference of the supporting portion 9, isadvantageously in the range from 6 mm to 7 mm, preferably of about 6.5mm.

The side sections 21 connect to opposite ends of the bottom section 20with an orientation tangent to the arc of a circle of the bottom section20.

A side edge 30 in an intersection region of the side sections 21 of thecam seats 11 with the outer circumference of the supporting portion 9 isadvantageously beveled, e.g. with a bevel radius of 0.5 mm.

The outer surface of the supporting portion 9 between two cam seats 11,respectively, is preferably cylindrical and concentric with respect tothe rotation axis 6. The connecting portion 7 and the support portion 9can be advantageously formed in a single piece with continuity ofmaterial.

The shape features of the supporting portion 9 allow an accurate andcost-effective manufacturing thereof, a favorable balance for rotationalmovements, and low friction between the cam seats 11 and thecam-follower members 13, which will be described below.

Depending on the size and weight of the coils 4 to be wound and unwound,and thus of the supporting cores 2, the supporting portion 9 of thespindle 1 can be made with different axial lengths and diameters.Advantageously, the shape and size of the individual cam seats 11 mayremain unchanged for a plurality of different diameters of thesupporting portion 9.

In advantageous and preferred embodiments, with the geometric shape andsize of the cam seats 11 described above, and with the arrangement ofthree cam seats 11 at an angular pitch of 120°:

-   -   for a diameter 31 of the supporting portion 9 of 45 mm, the        angular actuation stroke 16 is 15° (FIG. 15),    -   for a diameter 31 of the supporting portion 9 of 62 mm, the        angular actuation stroke 16 is 11.5° (FIG. 16),    -   for a diameter 31 of the supporting portion 9 of 82 mm, the        angular actuation stroke 16 is 10.7° (FIG. 17),    -   for a diameter 31 of the supporting portion 9 of 102 mm, the        angular actuation stroke 16 is 7.5° (FIG. 18).

In accordance with an embodiment (FIGS. 1, 2), the central shaft 5forms, on two opposite sides of the supporting portion 9, a first rearbearing seat 32 in the shape of a cylindrical step and a first frontbearing seat 33 in the shape of a cylindrical step, which accommodate arear bearing 34 and a front bearing 35 for rotationally supporting thesupporting cage 14 with respect to the central shaft 5 about therotation axis 6.

Detailed Description of the Locking Bodies 12 and Cam-Follower Members13

In accordance with an embodiment, the locking bodies 12 are preferablymade of a metal material, such as steel, for example, and form aradially outer engagement surface 36, preferably shaped as part of acylinder, intended for a pressing contact engagement against an intradosof the winding core 2. The engagement surface 36 preferably has agreater length in the direction of the rotation axis 6 than the widththereof in the circumferential direction with respect to the rotationaxis 6. At two opposite longitudinal ends 37 of the locking body 12, theengagement surface 36 is beveled or inclined in a radially inwarddirection so as to reduce the risk of snagging with the intrados of thewinding core 2 and the risk of damage to the locking body 12 or thewinding core 2 during their mutual engagement and disengagement.Furthermore, the inclination of the engagement surfaces 36 at theopposite longitudinal ends 37 facilitates a radially inward displacementof the locking bodies 12 “freely hanging” in the supporting cage 14during the insertion of the support spindle 1 into the winding core 2.

The locking body 12 also forms sliding surfaces 38, 39 transverse to theengagement surface 36, in particular two longitudinal sliding surfaces38 which are planar and parallel to each other and to the rotation axis6, and/or two transverse sliding surfaces 39 which are planar andorthogonal to the rotation axis 6 (FIG. 1).

The sliding surfaces 38, 39 are shaped in a complementary manner withcorresponding guiding surfaces 40, 41 of the guide seats 15 of thesupporting cage 14 to retain the locking bodies 12 in the guide seats 15in a radially sliding manner with respect to the rotation axis 6.

Furthermore, the locking bodies 12 form a radially inner surface 42facing the supporting portion 9 and which either forms or accommodatesone or more cam-follower members 13 (FIGS. 2, 3, 5). In accordance withan embodiment, the cam-follower members 13 are rolling bodies(preferably made of metal, e.g., steel) rotatably received in cavities43 formed in the radially inner surfaces 42 and contact the cam seats 11with rolling friction. Alternatively, the cam-follower members 13 can bedirectly formed from the locking bodies 12 and contact the cam seats 11with sliding friction.

Advantageously, the cam-follower members 12 are elongated cylindricalbodies inserted in the longitudinal direction (along the rotation axis6) into the corresponding cavities 43 which are partially cylindrical inshape and extending in a direction parallel to the rotation axis 6. Theplanned positioning of the cam-follower members 12 in the cavities 43can be ensured by a positioning dowel 50 screwed into a positioning holeof the locking body 12 (FIG. 2).

According to an embodiment, the radially inner surface 42 of the lockingbodies 12 forms two side cavities 44, arranged on two opposite sideswith respect to the cam-follower member 13 to obviate the risk of spaceviolations between the locking body 12 and the supporting portion 9,particularly when the locking body 12 is in the retracted position (FIG.3) radially closer to the central shaft 5. The side cavities 44 aredelimited, on one side, by the cam-follower member 13, and on the otherside, by one of two side guide walls 45 extending on each longitudinalside of the locking body 12, projecting towards the interior of thesupport spindle 1 and forming the longitudinal sliding surfaces 38 (FIG.3).

This configuration reconciles the needs of having to avoid spaceencroachments within the support spindle 1 during the relative actuationrotations, lightening the support spindle 1, and providing asufficiently long radial guide for the locking bodies 12.

The total radial stroke 24 of the locking bodies 12 is for example inthe range from 3 mm to 8 mm, preferably from 4 mm to 6 mm, preferably ofabout 5 mm.

In the retracted position, the locking bodies 12 preferably protrudewith respect to an outer surface 47 of the supporting cage 14, e.g. withan initial radial protrusion value 46 in the range from 5% to 15% of thetotal radial stroke 24, preferably with an initial radial protrusionvalue 46 of 10% of the total radial stroke 24, e.g. by 0.5 mm (FIGS. 3,5).

Each locking body 12 further forms one or more, preferably two stopprotrusions 48 which abut against the corresponding end-of-strokesurfaces 49 of the supporting cage 14 when the locking body 12 reachesthe expanded position. Thereby, a complete release and loss of thelocking bodies 12 out of the guide seats 15 is prevented, e.g. when thesupport spindle 1 is not inserted into a winding core 2 (FIG. 2).

Detailed Description of the Supporting Cage 14.

According to an embodiment, the supporting cage 14 can be made of metal,such as steel, for example, and comprise a tubular wall 51,concentrically inserted on the supporting portion 9 of the central shaft5, and having an outer surface 47, preferably cylindrical, and a(radially) inner surface 52 facing the supporting portion 9 of thecentral shaft 5.

The inner surface 52 forms, on two opposite sides with respect to theguide seats 15, a second rear bearing seat 53 in the shape of acylindrical step and a second front bearing seat 54 in the shape of acylindrical step which accommodate (outer rings of) the rear 34 andfront 35 bearings for rotatably supporting the bearing cage 14 withrespect to the central shaft 5 about the rotation axis 6.

The guiding seats 15 are formed by through openings in the tubular wall51, delimited by the longitudinal guiding surfaces 40 and transverseguiding surfaces 41 for the guided sliding support of the locking bodies12 (FIGS. 1.2, 3, 4).

The possibility of relative rotation of the locking bodies 12 withrespect to the supporting portion 9 of the central shaft 5 is ensured bythe rotatable support of the supporting cage 14 with respect to thecentral shaft 5. The relative rotation angle is defined and limited bythe radial end stop (stop protrusions 48, FIG. 2) of the locking bodies12 in the expanded position and by two opposite rotational end stopsmade by each cam seat 11 together with the corresponding cam-followermember 13 (FIG. 5).

According to an embodiment, on the front side 10 of the support spindle1, the supporting cage 14 is beveled, rounded, or tapered, so as tofacilitate the insertion of the support spindle 1 into the winding core2.

Advantageously, the supporting cage 14 is axially locked on the centralshaft 5 by an end cap 55 fixed to the front side 10 by means of a screwscrewed into a threaded hole formed in the front surface of the centralshaft 5. The end cap 55 is advantageously beveled, rounded, or taperedin accordance with the corresponding bevel or taper of the supportingcage 14.

The rear bearing 34 is a tapered roller bearing, adapted to support thesupporting cage 14 axially and radially, while the front bearing 35 ispreferably a radial bearing, such as a ball bearing. The supporting cage14 may form one or more ejection through-holes 56, in communication withthe second rear bearing seat 53, for a tool (such as a pin) to accessfor ejecting the outer ring of the tapered bearing from the second rearbearing seat 53 (FIG. 2). Furthermore, an annular dust protection disc59 can be arranged within the supporting cage 14 between the rearbearing 34 and the cam-follower members 13.

In accordance with a further embodiment (FIGS. 9, 10, 11), the supportspindle 1 may form a plurality of, preferably two, supporting portions9, 9′ of different diameters, which are concentric and positionedaxially next to each other, as well as a plurality of correspondingsupporting cages 14, 14′ of different diameters, which are concentricand positioned axially next to each other, with the smaller diametercage positioned more on the front side 10 of the support spindle 1, forversatile use of the support spindle 1 in combination with winding cores2 having different diameters.

In accordance with yet another embodiment (FIGS. 19, 20, 21, 22), thesupport spindle 1 may comprise a positioning and ejection flange 57axially sliding with respect to the central shaft 5 and guided, forexample, by a plurality of guiding grooves 58 parallel to the rotationaxis 6, formed in the outer surface of the supporting cage 14 (FIGS. 19,20).

In accordance with a further embodiment, the supporting cage 14, 14′ mayform one or more radial friction protrusions 60 (FIG. 22) adapted toengage the core 2 constantly in direct contact and with a friction suchas to ensure minimum torque transmission from the core 2 to thesupporting cage 14, 14′ even when the locking bodies 12 are not (yet orno longer) activated. This obviates a problem of loss of control overthe core during the almost complete unwinding or at the beginning of thewinding operation when, due to the small winding diameter, the corerotation speed is very high with the transport speed of thewound/unwound material being equal.

The positioning and ejection flange 57 can provide an axial supportreference for the core 2 during the steps of winding and unwinding thecoil 4, as well as can act as an ejection pusher for easierdisengagement of the support spindle 1 from the core 2.

The invention has numerous advantages that arise from its individualcharacteristics and from the synergy of their combination, including:

-   -   the reduction or minimization of the drive rotation between the        neutral position and the fully engaged position,    -   the possibility of an automatic return to the neutral position,    -   optimized contact between the support mandrel and the winding        core thanks to the association of a single cam follower to each        locking body,    -   the prevention of pressure concentrations or excessive uneven        pressures on the winding core,    -   protection against overloads and ease of rotation in any        operating situation, at least also due to the presence of an        axial bearing,    -   high mechanical resistance to support very heavy rolls and high        wear resistance, due to the possibility of maximizing the        diameter of the support portion and of using specifically        hardened materials, for example for the support cage, as well as        thanks to manufacturing the connection portion and the support        portion in a single metal piece,    -   a reduced number of individual components that facilitate        maintenance, repair and cleaning, at least in part with the        components in an assembled configuration,    -   flexible adaptability of geometric parameters within an overall        length set by the project, and therefore adaptable to different        dimensions of winding cores,    -   easy and quick access to and replacement of the support cage        and/or of the locking bodies, thanks to the closing cap screwed        to the front.

REFERENCE NUMERALS IN THE FIGURES

-   1 support spindle-   2 winding core-   3 windable material-   4 coil-   5 central shaft-   6 rotation axis-   7 connecting portion-   8 rear side-   9, 9′ supporting portion-   10 front side-   11 cam seat-   12 locking bodies-   13 cam-follower members-   14, 14′ supporting cage-   15 guide seats-   16 angular actuation stroke-   17 first cam surface-   18 second cam surface-   19 symmetry plane-   20 bottom section-   21 side section-   22 cam angle-   23 radial depth of cam seat-   24 total radial stroke-   25 circumferential width of cam seat-   26 fixing holes-   27 supporting and moving system-   28 actuation motor-   29 brake-   30 side edge of cam seat-   31 supporting portion diameter-   32 first rear bearing seat-   33 first front bearing seat-   34 rear bearing-   35 front bearing-   36 engagement surface-   37 opposite longitudinal ends of the locking body-   38 longitudinal sliding surface-   39 transverse sliding surface-   40 longitudinal guiding surface-   41 transverse guiding surface-   42 radially inner surface of locking body-   43 cavity for rolling element-   44 side cavities-   45 side guide wall-   46 initial radial protrusion value-   47 outer surface of supporting cage-   48 stop protrusion-   49 end-of-stroke surface-   50 positioning dowel-   51 tubular wall of supporting cage-   52 inner surface of supporting cage-   53 second rear bearing seat-   54 second front bearing seat-   55 closing cap-   56 ejection holes-   57 positioning and ejection flange-   58 guiding grooves-   59 dust protection disc-   60 friction protrusions

1. A support spindle (1) to engage a tubular winding core (2) forwinding and unwinding windable material (3) to form a coil (4),comprising: A) a central shaft (5) defining a rotation axis (6) andforming: a connecting portion (7) on a rear side (8) of the supportspindle (1), a supporting portion (9) extending from the connectingportion (8) along the rotation axis (6) towards a front side (10) of thesupport spindle (1), a plurality of cam seats (11) formed in thesupporting portion (9), B) a plurality of locking bodies (12) arrangedradially outside the supporting portion (9) and in contact, by means ofcam follower members (13), with the cam seats (11), C) a supporting cage(14) connected to the central shaft (5) and forming a plurality of guideseats (15) which accommodate and position the locking bodies (12) sothat the locking bodies (12) can slide radially to the rotation axis (6)with respect to the central shaft (5) and rotate about the rotation axis(6) with respect to the central shaft (5), wherein the cam seats (11)and cam follower members (13) are shaped so that a relative rotationbetween the locking bodies (12) and the central shaft (5) about therotation axis (6), along an angular stroke (16), causes a radialdisplacement of the locking bodies (12) between a radially innerretracted position, and a radially outer expanded position, fordisengaging and engaging the support spindle (1) with the winding core(2), wherein the cam follower members (13) form a first convex camsurface (17) in contact with a second concave cam surface (18) of thecorresponding cam seat (11).
 2. A support spindle (1) according to claim1, wherein, on a sectional plane orthogonal to the rotation axis (6),the first convex cam surface (17) has a circular arc shape and thesecond concave cam surface (18) has a symmetrical shape with respect toa symmetry plane (19) radial to the rotation axis (6), with anarch-shaped bottom section (20) and two opposite side sections (21). 3.A support spindle (1) according to claim 1, wherein a radial depth (23)of the cam seat (11) is greater than the total radial stroke (24) of thelocking bodies (12) and a circumferential width (25) of the cam seat(11) is greater than four times the radial depth (23) of the cam seat(10).
 4. A support spindle (1) according to claim 1, wherein: theconnecting portion (7) comprises a circular disc-shaped connectingflange extending on a plane orthogonal to the rotation axis (6) andforming a plurality of fixing holes (26), the supporting portion (9) hasan elongated shape with a cylindrical outer surface in which the camseats (11) are formed, the cam seats (11) are extended parallel to therotation axis (6) along the entire supporting portion (9) and have aconstant cross-section shape along the rotation axis (6). the supportingportion (9) comprises three cam seats (11) evenly distributed at anangular pitch of 120°.
 5. A support spindle (1) according to claim 1,wherein the bottom section (20) is shaped as an arc of a circle. 6.(canceled)
 7. A support spindle (1) according to claim 1, wherein theside sections (21) are joined at opposite ends of the bottom section(20) with an orientation tangent to the arc of a circle of the bottomsection (20) and wherein a side edge (30) in an intersection region ofthe side sections (21) with an outer circumference of the supportingportion (9) is beveled.
 8. (canceled)
 9. A support spindle (1) accordingto claim 1, wherein the locking bodies (12) form: (A) a radially outer,cylinder part-shaped engagement surface (36) having a length in thedirection of the rotation axis (6) greater than a width thereof incircumferential direction with respect to the rotation axis (6), whereinat two opposite longitudinal ends (37) of the locking body (12) theengagement surface (36) is inclined in a radially inward direction, B)sliding surfaces (38, 39), transverse to the engagement surface (36),shaped in a complementary manner with corresponding guiding surfaces(40, 41) of the guiding seats (15) of the supporting cage (14), C) aradially inner surface (42) facing the supporting portion (9) andaccommodating one or more rolling cam-follower members (13), D) one ormore stop protrusions (48) which abut against corresponding end ofstroke surfaces (49) of the supporting cage (14) when the locking body(12) reaches the expanded position.
 10. A support spindle (1) accordingto claim 9, wherein the cam follower-members (12) are elongatedcylindrical bodies inserted into the partially cylindrical-shapedcavities (43) in the direction parallel to the rotation axis (6).
 11. Asupport spindle (1) according to claim 9, wherein the radially innersurface (42) of the locking bodies (12) forms two side cavities (44),arranged on two opposite sides with respect to the cam-follower member(13), wherein said side cavities (44) are delimited, on one side by thecam-follower member (13) and on the other side by one of two side guidewalls (45) extended on each longitudinal side of the locking body (12),protruding towards the inside of the support spindle (1).
 12. (canceled)13. A support spindle (1) according to claim 1, wherein in the retractedposition the locking bodies (12) protrude with respect to an outersurface (47) of the supporting cage (14), with an initial radialprotrusion (46) in the range from 5% to 15% of the total radial stroke(24), or 10% of the total radial stroke (24), or 0.5 mm.
 14. A supportspindle (1) according to claim 1, wherein the supporting cage (14)comprises a tubular wall (51), inserted concentrically on the supportingportion (9) of the central shaft (5), and having a cylindrical outersurface (47) and an inner surface (52) facing the supporting portion(9), wherein the guiding seats (15) are formed by through openings inthe tubular wall (51), delimited by longitudinal guiding surfaces (40)and transverse guiding surfaces (41) for the guided sliding support ofthe locking bodies (12), wherein on the front side (10) of the supportspindle (1) the supporting cage (14) is beveled so that the supportspindle (1) can be more easily inserted into the winding core (2),wherein the supporting cage (14) is locked axially on the central shaft(5) by means of a closing plug (55) screwed to a front surface of thecentral shaft (5), wherein the closing cap (55) is also beveledcontinuing the beveling of the supporting cage (14).
 15. A supportspindle (1) according to claim 1, comprising two of said concentricsupporting portions (9, 9′) and having different diameters, as well as aplurality of said concentric supporting cages (14, 14′) having differentdiameters and positioned axially next to each other, with the smallerdiameter supporting cage (14, 14′) positioned more on the front side(10) of the support spindle (1).
 16. A support spindle (1) according toclaim 1, comprising a positioning and ejection flange (57) axiallysliding with respect to the central shaft (5) and guided by a pluralityof guiding grooves (58) parallel to the rotation axis (6), formed in anouter surface of the supporting cage (14).
 17. A support spindle (1)according to claim 1, wherein the supporting cage (14, 14′) forms one ormore radial friction protrusions (60) adapted to engage the core (2)constantly in direct contact and with a friction such as to ensureminimum torque transmission from the core (2) to the supporting cage(14, 14′) even when the locking bodies (12) are not yet or no longeractivated.
 18. A support spindle (1) according to claim 1, wherein toeach of said locking bodies (12) is associated exactly and only one ofsaid cam follower members (13).
 19. A support spindle (1) according toclaim 2, wherein to each of said locking bodies (12) is associatedexactly and only one of said cam follower members (13).
 20. A supportspindle (1) according to claim 1, wherein each said locking body (12)forms a radially internal surface (42) facing the support portion (9)and forming a partially cylindrical cavity (43) extending in a directionparallel to the rotation axis (6), in which said cavity (43) rotatablyaccommodates one of said cam follower members (13) having an elongatedcylindrical shape and being extended in a direction parallel to the axisof rotation (6), wherein between respectively one locking body (12) andthe support portion (9) there is interposed: only one of said camfollower members (13) having elongated cylindrical shape, or a group ofsaid cam follower members (13) of elongated cylindrical shape, in whichall said cam follower members (13) of the group are positioned andoriented concentric with each other and parallel to the rotation axis(6).
 21. A support spindle (1) according to claim 2, wherein each saidlocking body (12) forms a radially internal surface (42) facing thesupport portion (9) and forming a partially cylindrical cavity (43)extending in a direction parallel to the rotation axis (6), in whichsaid cavity (43) rotatably accommodates one of said cam follower members(13) having an elongated cylindrical shape and being extended in adirection parallel to the axis of rotation (6), wherein betweenrespectively one locking body (12) and the support portion (9) there isinterposed: only one of said cam follower members (13) having elongatedcylindrical shape, or a group of said cam follower members (13) ofelongated cylindrical shape, in which all said cam follower members (13)of the group are positioned and oriented concentric with each other andparallel to the rotation axis (6).